Medical imaging technology has advanced rapidly in recent years. A major thrust of the advancement has come through the use of nuclear magnetic resonance (NMR) technology to provide clinical magnetic resonance imaging (MRI) systems.
The principles of NMR were first described in about 1946, however, MRI instrumentation has only been used since 1973. In the time period since 1973, MRI has rapidly established itself as a superior imaging modality, in certain situations, relative to x-ray, CT scanning and ultrasound. For example, MRI is a modality of choice for high resolution imaging of soft tissue. In addition, use of proper MRI technique allows distinction of areas of edema, hemorrhage, tumors (e.g. bone tumor) and flowing blood which are typically difficult to distinguish using, for example, x-ray CT.
Many MRI's which are presently available create a magnetic field using cylindrical superconducting magnets which may obstruct access to the patient during scanning. More recently, open MRI systems have become available which permit access to the patient during imaging procedures. Hence, this allows the practitioner an opportunity to perform diagnostic or therapeutic procedures while performing MRI scans. This new field in medicine is called MRT (magnetic resonance therapy). Unfortunately, however, many of the instruments which may be used to perform procedures during imaging create artifact on the resulting image.
Accordingly, there is a need for materials that can be used during diagnostic imaging procedures, especially MRI, with controlled production of artifact on the resulting image. There is also a need for instruments which may be used during scanning with reduced obstruction of visualization during scanning. Moreover, there is a need for instruments which minimally obscure visualization during scanning and which can resist structural deformity during use. Furthermore, there is the need to develop a technology to control the artifact of the instrument which is caused by the magnetic property of its material.